1. **State the problem:** Find 2/3 of 78. 2. **Formula:** To find a fraction of a number, multiply the fraction by the number. 3. **Apply the formula:** $$\frac{2}{3} \times 78$$ 4. **Calculate:** $$= \frac{2 \times 78}{3} = \frac{156}{3}$$ 5. **Simplify:** $$= 52$$ 6. **Answer:** 2/3 of 78 is 52.